2020/06/30 by Kosuke Mitarai, Keisuke Fujii · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.22331/q-2021-01-28-388
published as Quantum 5, 388 (2021) · 7 pages, 2 figures
arxiv created 2021/01/25 · arxiv updated 2021/02/03
As the hardware technology for quantum computing advances, its possible applications are actively searched and developed. However, such applications still suffer from the noise on quantum devices, in particular when using two-qubit gates whose fidelity is relatively low. One way to overcome this difficulty is to substitute such non-local operations by local ones. Such substitution can be performed by decomposing a non-local channel into a linear combination of local channels and simulating the original channel with a quasiprobability-based method. In this work, we first define a quantity that we call channel robustness of non-locality, which quantifies the cost for the decomposition. While this quantity is challenging to calculate for a general non-local channel, we give an upper bound for a general two-qubit unitary channel by providing an explicit decomposition. The decomposition is obtained by generalizing our previous work whose application has been restricted to a certain form of two-qubit unitary. This work develops a framework for a resource reduction suitable for first-generation quantum devices.